[13pt] Develop and test levee solution to better restrict inundation in protected areas

[RyanSpies-NOAA]

It seems that most of the FIM feedback we've received for leveed areas is overpredicted inundation showing up in the protected areas behind levees. Forcing HAND to created protected catchment "islands" seems like it is going to be a sizeable challenge with the existing NLD data and FIM workflow. One alternative might be to use the protected area polygons to create FIM "exclusion zones" where we mask any/all inundation and then find a streamlined way to make sure that is communicated alongside the FIM service. Another option could be to use the levee feature elevation (min, max, median?) to create an artificial "plateau" in the HAND values for the protected area zones.

[RyanSpies-NOAA]

Refer to vlab ticket #104064 for example issues relating to FIM performance near levee features.

[CarsonPruitt-NOAA]

Brainstorming meeting about how to address this issue.

Datasets

• NLD levee features (polylines) with elevations along the levee
• NLD protected areas (polygons)

Possible solutions

• Artificially elevate levee protected areas
  • “Plateau” height = min, max, median of levee elev ??
  • Infinite height (never allow overtopping)
• Mask protected areas during inundation generation
  • Service to show disclaimer with protected areas
  • 0: no inundation, 1: inundated, 2: excluded area (levee protected, NWM water body)
• Combination of 1 & 2
  • Infinite height of levee features (force hydroID catchments to reflect levee features)
  • Mask out the protected areas from REM during SRC calculation (
  • Rewire inundation.py to include a value of 2: excluded area
• LISFLOOD for leveed areas

Other issues

• HUC8 boundary issues

[mluck]

Was this issue addressed by #690?

[mluck]

Closed by #690 and #845